Multi-conditional 'if' statements

In programming, it is often necessary to execute a piece of code based on more than one condition. To accomplish this, PHP provides a few ways to evaluate a code block based on multiple conditions. Although the desired result can be achieved by simply embedding if statements within other if statements, this is often an excessive and confusing way to accomplish the desired effect. To help remedy this problem, special conditional operators "and" (&&) and "or" (||) are provided. These operators separate multiple conditions within an if statement and determine the final outcome of an evaluation. For example, consider the following statement:

If Billy has $5, and his mom says itís okay, he can have a candy bar.

We already learned how to code this conditional statement by embedding two if statements as shown below:

As you can see, we have used the "and" operator to combine the original two separate conditional statements into a single conditional statement.

Note: The use of parentheses in the above example is to ensure that each separate conditional statement is evaluated properly before the results of those conditions are evaluated through the "and" operator.

If all conditions that are combined using the "and" operator must evaluate to "true" for the statement to be true, then when using the "or" operator only a single condition of the combined conditions must evaluate to "true" in order for the statement to be true. For example, if we modified our example to read:

In this example, the complexity and inefficiency of our code increases because we have to duplicate code twice. To make this code more efficient, we can combine these two conditional statements using our new conditional operators.

The same statement using these operators would look something like this: